Silica mesoscopic order

Lu Y, Yang Y, Sellinger A, Lu M, Huang J, Pan H, Haddad R, Lopez G, Bums AR, Sasaki DY, Shelnutt J, Brinker CJ. Self-assembly of mesoscopically ordered chromatic polydiacety-lene/silica nanocomposites. Nature 2001 410 913-917. 

Stucky11751 developed a procedure for the synthesis of sponge-like silica membranes with 3-D meso-macrostructures. The process utilizes multiphase media composed of a mesoscopically ordered block copolymer-silica phase that macroscopically separates from an electrolyte phase. The different characteristic lengthscales in hierarchically organized composite structures can be independently adjusted. 

A more recent trend in polymer materials research is the hybridization of cellulosic polysaccharides with inorganic compounds natural and synthetic layered clays, silica, zeolites, metal oxides, and apatites are employable as nanoscale components. In addition, if mesoscopic assemblies such as liquid-crystalline ordering are used in the construction of new compositional systems, the variety of functionalized cellulosic materials will be further expanded. 

One of the first examples of mesoscopic-macroscopic two-dimensional ordering within a structure involved a bacterial superstructure formed from the co-aligned multicellular filaments of Bacillus subtilis that was used to template macroporous fibers of either amorphous or ordered mesoporous silica [82], The interfilament space was mineralized with mesoporous silica and, following removal of the organic, a macroporous framework with 0.5 pm wide channels remained. Mesoporous silica channel walls in this hierarchical structure were curved and approximately 100 nm in thickness. Dense, amorphous walls were obtained by replacing the surfactant-silicate synthesis mixture with a silica sol solution. The difference in the mode of formation between porous and non-porous wall structures was explained in terms of assembly from close-packed mesoporous silica coated bacterial filaments in the former compared to consolidation of silica nanoparticles within interfilament voids in the latter. 

Yao N., Ku A.Y., Nakagawa N., Lee T., SavUle D.A., Aksay I.A. Disorder-order transition in mesoscopic silica thin films. Chem. Mater. 2000 12 1536-1548 Yun H.-S., Miyazawa K., Zhou H., Honma I., Kuwabara M. Synthesis of mesoporous thin Ti02 films with hexagonal pore structures using triblock copolymer templates. Adv. Mater. 2001 13 1377-1380... 

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